sys_lwp.c revision 1.52.12.1 1 /* $NetBSD: sys_lwp.c,v 1.52.12.1 2012/02/24 09:11:48 mrg Exp $ */
2
3 /*-
4 * Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nathan J. Williams, and Andrew Doran.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Lightweight process (LWP) system calls. See kern_lwp.c for a description
34 * of LWPs.
35 */
36
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.52.12.1 2012/02/24 09:11:48 mrg Exp $");
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/pool.h>
43 #include <sys/proc.h>
44 #include <sys/types.h>
45 #include <sys/syscallargs.h>
46 #include <sys/kauth.h>
47 #include <sys/kmem.h>
48 #include <sys/sleepq.h>
49 #include <sys/lwpctl.h>
50 #include <sys/cpu.h>
51
52 #include <uvm/uvm_extern.h>
53
54 #define LWP_UNPARK_MAX 1024
55
56 static syncobj_t lwp_park_sobj = {
57 SOBJ_SLEEPQ_LIFO,
58 sleepq_unsleep,
59 sleepq_changepri,
60 sleepq_lendpri,
61 syncobj_noowner,
62 };
63
64 static sleeptab_t lwp_park_tab;
65
66 void
67 lwp_sys_init(void)
68 {
69 sleeptab_init(&lwp_park_tab);
70 }
71
72 int
73 sys__lwp_create(struct lwp *l, const struct sys__lwp_create_args *uap,
74 register_t *retval)
75 {
76 /* {
77 syscallarg(const ucontext_t *) ucp;
78 syscallarg(u_long) flags;
79 syscallarg(lwpid_t *) new_lwp;
80 } */
81 struct proc *p = l->l_proc;
82 struct lwp *l2;
83 struct schedstate_percpu *spc;
84 vaddr_t uaddr;
85 ucontext_t *newuc;
86 int error, lid;
87
88 newuc = kmem_alloc(sizeof(ucontext_t), KM_SLEEP);
89 error = copyin(SCARG(uap, ucp), newuc, p->p_emul->e_ucsize);
90 if (error) {
91 kmem_free(newuc, sizeof(ucontext_t));
92 return error;
93 }
94
95 /* XXX check against resource limits */
96
97 uaddr = uvm_uarea_alloc();
98 if (__predict_false(uaddr == 0)) {
99 kmem_free(newuc, sizeof(ucontext_t));
100 return ENOMEM;
101 }
102
103 error = lwp_create(l, p, uaddr, SCARG(uap, flags) & LWP_DETACHED,
104 NULL, 0, p->p_emul->e_startlwp, newuc, &l2, l->l_class);
105 if (__predict_false(error)) {
106 uvm_uarea_free(uaddr);
107 kmem_free(newuc, sizeof(ucontext_t));
108 return error;
109 }
110
111 lid = l2->l_lid;
112 error = copyout(&lid, SCARG(uap, new_lwp), sizeof(lid));
113 if (error) {
114 lwp_exit(l2);
115 kmem_free(newuc, sizeof(ucontext_t));
116 return error;
117 }
118
119 /*
120 * Set the new LWP running, unless the caller has requested that
121 * it be created in suspended state. If the process is stopping,
122 * then the LWP is created stopped.
123 */
124 mutex_enter(p->p_lock);
125 lwp_lock(l2);
126 spc = &l2->l_cpu->ci_schedstate;
127 if ((SCARG(uap, flags) & LWP_SUSPENDED) == 0 &&
128 (l->l_flag & (LW_WREBOOT | LW_WSUSPEND | LW_WEXIT)) == 0) {
129 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) {
130 KASSERT(l2->l_wchan == NULL);
131 l2->l_stat = LSSTOP;
132 p->p_nrlwps--;
133 lwp_unlock_to(l2, spc->spc_lwplock);
134 } else {
135 KASSERT(lwp_locked(l2, spc->spc_mutex));
136 l2->l_stat = LSRUN;
137 sched_enqueue(l2, false);
138 lwp_unlock(l2);
139 }
140 } else {
141 l2->l_stat = LSSUSPENDED;
142 p->p_nrlwps--;
143 lwp_unlock_to(l2, spc->spc_lwplock);
144 }
145 mutex_exit(p->p_lock);
146
147 return 0;
148 }
149
150 int
151 sys__lwp_exit(struct lwp *l, const void *v, register_t *retval)
152 {
153
154 lwp_exit(l);
155 return 0;
156 }
157
158 int
159 sys__lwp_self(struct lwp *l, const void *v, register_t *retval)
160 {
161
162 *retval = l->l_lid;
163 return 0;
164 }
165
166 int
167 sys__lwp_getprivate(struct lwp *l, const void *v, register_t *retval)
168 {
169
170 *retval = (uintptr_t)l->l_private;
171 return 0;
172 }
173
174 int
175 sys__lwp_setprivate(struct lwp *l, const struct sys__lwp_setprivate_args *uap,
176 register_t *retval)
177 {
178 /* {
179 syscallarg(void *) ptr;
180 } */
181
182 return lwp_setprivate(l, SCARG(uap, ptr));
183 }
184
185 int
186 sys__lwp_suspend(struct lwp *l, const struct sys__lwp_suspend_args *uap,
187 register_t *retval)
188 {
189 /* {
190 syscallarg(lwpid_t) target;
191 } */
192 struct proc *p = l->l_proc;
193 struct lwp *t;
194 int error;
195
196 mutex_enter(p->p_lock);
197 if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
198 mutex_exit(p->p_lock);
199 return ESRCH;
200 }
201
202 /*
203 * Check for deadlock, which is only possible when we're suspending
204 * ourself. XXX There is a short race here, as p_nrlwps is only
205 * incremented when an LWP suspends itself on the kernel/user
206 * boundary. It's still possible to kill -9 the process so we
207 * don't bother checking further.
208 */
209 lwp_lock(t);
210 if ((t == l && p->p_nrlwps == 1) ||
211 (l->l_flag & (LW_WCORE | LW_WEXIT)) != 0) {
212 lwp_unlock(t);
213 mutex_exit(p->p_lock);
214 return EDEADLK;
215 }
216
217 /*
218 * Suspend the LWP. XXX If it's on a different CPU, we should wait
219 * for it to be preempted, where it will put itself to sleep.
220 *
221 * Suspension of the current LWP will happen on return to userspace.
222 */
223 error = lwp_suspend(l, t);
224 if (error) {
225 mutex_exit(p->p_lock);
226 return error;
227 }
228
229 /*
230 * Wait for:
231 * o process exiting
232 * o target LWP suspended
233 * o target LWP not suspended and L_WSUSPEND clear
234 * o target LWP exited
235 */
236 for (;;) {
237 error = cv_wait_sig(&p->p_lwpcv, p->p_lock);
238 if (error) {
239 error = ERESTART;
240 break;
241 }
242 if (lwp_find(p, SCARG(uap, target)) == NULL) {
243 error = ESRCH;
244 break;
245 }
246 if ((l->l_flag | t->l_flag) & (LW_WCORE | LW_WEXIT)) {
247 error = ERESTART;
248 break;
249 }
250 if (t->l_stat == LSSUSPENDED ||
251 (t->l_flag & LW_WSUSPEND) == 0)
252 break;
253 }
254 mutex_exit(p->p_lock);
255
256 return error;
257 }
258
259 int
260 sys__lwp_continue(struct lwp *l, const struct sys__lwp_continue_args *uap,
261 register_t *retval)
262 {
263 /* {
264 syscallarg(lwpid_t) target;
265 } */
266 int error;
267 struct proc *p = l->l_proc;
268 struct lwp *t;
269
270 error = 0;
271
272 mutex_enter(p->p_lock);
273 if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
274 mutex_exit(p->p_lock);
275 return ESRCH;
276 }
277
278 lwp_lock(t);
279 lwp_continue(t);
280 mutex_exit(p->p_lock);
281
282 return error;
283 }
284
285 int
286 sys__lwp_wakeup(struct lwp *l, const struct sys__lwp_wakeup_args *uap,
287 register_t *retval)
288 {
289 /* {
290 syscallarg(lwpid_t) target;
291 } */
292 struct lwp *t;
293 struct proc *p;
294 int error;
295
296 p = l->l_proc;
297 mutex_enter(p->p_lock);
298
299 if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
300 mutex_exit(p->p_lock);
301 return ESRCH;
302 }
303
304 lwp_lock(t);
305 t->l_flag |= (LW_CANCELLED | LW_UNPARKED);
306
307 if (t->l_stat != LSSLEEP) {
308 lwp_unlock(t);
309 error = ENODEV;
310 } else if ((t->l_flag & LW_SINTR) == 0) {
311 lwp_unlock(t);
312 error = EBUSY;
313 } else {
314 /* Wake it up. lwp_unsleep() will release the LWP lock. */
315 lwp_unsleep(t, true);
316 error = 0;
317 }
318
319 mutex_exit(p->p_lock);
320
321 return error;
322 }
323
324 int
325 sys__lwp_wait(struct lwp *l, const struct sys__lwp_wait_args *uap,
326 register_t *retval)
327 {
328 /* {
329 syscallarg(lwpid_t) wait_for;
330 syscallarg(lwpid_t *) departed;
331 } */
332 struct proc *p = l->l_proc;
333 int error;
334 lwpid_t dep;
335
336 mutex_enter(p->p_lock);
337 error = lwp_wait1(l, SCARG(uap, wait_for), &dep, 0);
338 mutex_exit(p->p_lock);
339
340 if (error)
341 return error;
342
343 if (SCARG(uap, departed)) {
344 error = copyout(&dep, SCARG(uap, departed), sizeof(dep));
345 if (error)
346 return error;
347 }
348
349 return 0;
350 }
351
352 int
353 sys__lwp_kill(struct lwp *l, const struct sys__lwp_kill_args *uap,
354 register_t *retval)
355 {
356 /* {
357 syscallarg(lwpid_t) target;
358 syscallarg(int) signo;
359 } */
360 struct proc *p = l->l_proc;
361 struct lwp *t;
362 ksiginfo_t ksi;
363 int signo = SCARG(uap, signo);
364 int error = 0;
365
366 if ((u_int)signo >= NSIG)
367 return EINVAL;
368
369 KSI_INIT(&ksi);
370 ksi.ksi_signo = signo;
371 ksi.ksi_code = SI_LWP;
372 ksi.ksi_pid = p->p_pid;
373 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred);
374 ksi.ksi_lid = SCARG(uap, target);
375
376 mutex_enter(proc_lock);
377 mutex_enter(p->p_lock);
378 if ((t = lwp_find(p, ksi.ksi_lid)) == NULL)
379 error = ESRCH;
380 else if (signo != 0)
381 kpsignal2(p, &ksi);
382 mutex_exit(p->p_lock);
383 mutex_exit(proc_lock);
384
385 return error;
386 }
387
388 int
389 sys__lwp_detach(struct lwp *l, const struct sys__lwp_detach_args *uap,
390 register_t *retval)
391 {
392 /* {
393 syscallarg(lwpid_t) target;
394 } */
395 struct proc *p;
396 struct lwp *t;
397 lwpid_t target;
398 int error;
399
400 target = SCARG(uap, target);
401 p = l->l_proc;
402
403 mutex_enter(p->p_lock);
404
405 if (l->l_lid == target)
406 t = l;
407 else {
408 /*
409 * We can't use lwp_find() here because the target might
410 * be a zombie.
411 */
412 LIST_FOREACH(t, &p->p_lwps, l_sibling)
413 if (t->l_lid == target)
414 break;
415 }
416
417 /*
418 * If the LWP is already detached, there's nothing to do.
419 * If it's a zombie, we need to clean up after it. LSZOMB
420 * is visible with the proc mutex held.
421 *
422 * After we have detached or released the LWP, kick any
423 * other LWPs that may be sitting in _lwp_wait(), waiting
424 * for the target LWP to exit.
425 */
426 if (t != NULL && t->l_stat != LSIDL) {
427 if ((t->l_prflag & LPR_DETACHED) == 0) {
428 p->p_ndlwps++;
429 t->l_prflag |= LPR_DETACHED;
430 if (t->l_stat == LSZOMB) {
431 /* Releases proc mutex. */
432 lwp_free(t, false, false);
433 return 0;
434 }
435 error = 0;
436
437 /*
438 * Have any LWPs sleeping in lwp_wait() recheck
439 * for deadlock.
440 */
441 cv_broadcast(&p->p_lwpcv);
442 } else
443 error = EINVAL;
444 } else
445 error = ESRCH;
446
447 mutex_exit(p->p_lock);
448
449 return error;
450 }
451
452 static inline wchan_t
453 lwp_park_wchan(struct proc *p, const void *hint)
454 {
455
456 return (wchan_t)((uintptr_t)p ^ (uintptr_t)hint);
457 }
458
459 int
460 lwp_unpark(lwpid_t target, const void *hint)
461 {
462 sleepq_t *sq;
463 wchan_t wchan;
464 kmutex_t *mp;
465 proc_t *p;
466 lwp_t *t;
467
468 /*
469 * Easy case: search for the LWP on the sleep queue. If
470 * it's parked, remove it from the queue and set running.
471 */
472 p = curproc;
473 wchan = lwp_park_wchan(p, hint);
474 sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
475
476 TAILQ_FOREACH(t, sq, l_sleepchain)
477 if (t->l_proc == p && t->l_lid == target)
478 break;
479
480 if (__predict_true(t != NULL)) {
481 sleepq_remove(sq, t);
482 mutex_spin_exit(mp);
483 return 0;
484 }
485
486 /*
487 * The LWP hasn't parked yet. Take the hit and mark the
488 * operation as pending.
489 */
490 mutex_spin_exit(mp);
491
492 mutex_enter(p->p_lock);
493 if ((t = lwp_find(p, target)) == NULL) {
494 mutex_exit(p->p_lock);
495 return ESRCH;
496 }
497
498 /*
499 * It may not have parked yet, we may have raced, or it
500 * is parked on a different user sync object.
501 */
502 lwp_lock(t);
503 if (t->l_syncobj == &lwp_park_sobj) {
504 /* Releases the LWP lock. */
505 lwp_unsleep(t, true);
506 } else {
507 /*
508 * Set the operation pending. The next call to _lwp_park
509 * will return early.
510 */
511 t->l_flag |= LW_UNPARKED;
512 lwp_unlock(t);
513 }
514
515 mutex_exit(p->p_lock);
516 return 0;
517 }
518
519 int
520 lwp_park(struct timespec *ts, const void *hint)
521 {
522 sleepq_t *sq;
523 kmutex_t *mp;
524 wchan_t wchan;
525 int timo, error;
526 lwp_t *l;
527
528 /* Fix up the given timeout value. */
529 if (ts != NULL) {
530 error = abstimeout2timo(ts, &timo);
531 if (error) {
532 return error;
533 }
534 KASSERT(timo != 0);
535 } else {
536 timo = 0;
537 }
538
539 /* Find and lock the sleep queue. */
540 l = curlwp;
541 wchan = lwp_park_wchan(l->l_proc, hint);
542 sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
543
544 /*
545 * Before going the full route and blocking, check to see if an
546 * unpark op is pending.
547 */
548 lwp_lock(l);
549 if ((l->l_flag & (LW_CANCELLED | LW_UNPARKED)) != 0) {
550 l->l_flag &= ~(LW_CANCELLED | LW_UNPARKED);
551 lwp_unlock(l);
552 mutex_spin_exit(mp);
553 return EALREADY;
554 }
555 lwp_unlock_to(l, mp);
556 l->l_biglocks = 0;
557 sleepq_enqueue(sq, wchan, "parked", &lwp_park_sobj);
558 error = sleepq_block(timo, true);
559 switch (error) {
560 case EWOULDBLOCK:
561 error = ETIMEDOUT;
562 break;
563 case ERESTART:
564 error = EINTR;
565 break;
566 default:
567 /* nothing */
568 break;
569 }
570 return error;
571 }
572
573 /*
574 * 'park' an LWP waiting on a user-level synchronisation object. The LWP
575 * will remain parked until another LWP in the same process calls in and
576 * requests that it be unparked.
577 */
578 int
579 sys____lwp_park50(struct lwp *l, const struct sys____lwp_park50_args *uap,
580 register_t *retval)
581 {
582 /* {
583 syscallarg(const struct timespec *) ts;
584 syscallarg(lwpid_t) unpark;
585 syscallarg(const void *) hint;
586 syscallarg(const void *) unparkhint;
587 } */
588 struct timespec ts, *tsp;
589 int error;
590
591 if (SCARG(uap, ts) == NULL)
592 tsp = NULL;
593 else {
594 error = copyin(SCARG(uap, ts), &ts, sizeof(ts));
595 if (error != 0)
596 return error;
597 tsp = &ts;
598 }
599
600 if (SCARG(uap, unpark) != 0) {
601 error = lwp_unpark(SCARG(uap, unpark), SCARG(uap, unparkhint));
602 if (error != 0)
603 return error;
604 }
605
606 return lwp_park(tsp, SCARG(uap, hint));
607 }
608
609 int
610 sys__lwp_unpark(struct lwp *l, const struct sys__lwp_unpark_args *uap,
611 register_t *retval)
612 {
613 /* {
614 syscallarg(lwpid_t) target;
615 syscallarg(const void *) hint;
616 } */
617
618 return lwp_unpark(SCARG(uap, target), SCARG(uap, hint));
619 }
620
621 int
622 sys__lwp_unpark_all(struct lwp *l, const struct sys__lwp_unpark_all_args *uap,
623 register_t *retval)
624 {
625 /* {
626 syscallarg(const lwpid_t *) targets;
627 syscallarg(size_t) ntargets;
628 syscallarg(const void *) hint;
629 } */
630 struct proc *p;
631 struct lwp *t;
632 sleepq_t *sq;
633 wchan_t wchan;
634 lwpid_t targets[32], *tp, *tpp, *tmax, target;
635 int error;
636 kmutex_t *mp;
637 u_int ntargets;
638 size_t sz;
639
640 p = l->l_proc;
641 ntargets = SCARG(uap, ntargets);
642
643 if (SCARG(uap, targets) == NULL) {
644 /*
645 * Let the caller know how much we are willing to do, and
646 * let it unpark the LWPs in blocks.
647 */
648 *retval = LWP_UNPARK_MAX;
649 return 0;
650 }
651 if (ntargets > LWP_UNPARK_MAX || ntargets == 0)
652 return EINVAL;
653
654 /*
655 * Copy in the target array. If it's a small number of LWPs, then
656 * place the numbers on the stack.
657 */
658 sz = sizeof(target) * ntargets;
659 if (sz <= sizeof(targets))
660 tp = targets;
661 else {
662 tp = kmem_alloc(sz, KM_SLEEP);
663 if (tp == NULL)
664 return ENOMEM;
665 }
666 error = copyin(SCARG(uap, targets), tp, sz);
667 if (error != 0) {
668 if (tp != targets) {
669 kmem_free(tp, sz);
670 }
671 return error;
672 }
673
674 wchan = lwp_park_wchan(p, SCARG(uap, hint));
675 sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
676
677 for (tmax = tp + ntargets, tpp = tp; tpp < tmax; tpp++) {
678 target = *tpp;
679
680 /*
681 * Easy case: search for the LWP on the sleep queue. If
682 * it's parked, remove it from the queue and set running.
683 */
684 TAILQ_FOREACH(t, sq, l_sleepchain)
685 if (t->l_proc == p && t->l_lid == target)
686 break;
687
688 if (t != NULL) {
689 sleepq_remove(sq, t);
690 continue;
691 }
692
693 /*
694 * The LWP hasn't parked yet. Take the hit and
695 * mark the operation as pending.
696 */
697 mutex_spin_exit(mp);
698 mutex_enter(p->p_lock);
699 if ((t = lwp_find(p, target)) == NULL) {
700 mutex_exit(p->p_lock);
701 mutex_spin_enter(mp);
702 continue;
703 }
704 lwp_lock(t);
705
706 /*
707 * It may not have parked yet, we may have raced, or
708 * it is parked on a different user sync object.
709 */
710 if (t->l_syncobj == &lwp_park_sobj) {
711 /* Releases the LWP lock. */
712 lwp_unsleep(t, true);
713 } else {
714 /*
715 * Set the operation pending. The next call to
716 * _lwp_park will return early.
717 */
718 t->l_flag |= LW_UNPARKED;
719 lwp_unlock(t);
720 }
721
722 mutex_exit(p->p_lock);
723 mutex_spin_enter(mp);
724 }
725
726 mutex_spin_exit(mp);
727 if (tp != targets)
728 kmem_free(tp, sz);
729
730 return 0;
731 }
732
733 int
734 sys__lwp_setname(struct lwp *l, const struct sys__lwp_setname_args *uap,
735 register_t *retval)
736 {
737 /* {
738 syscallarg(lwpid_t) target;
739 syscallarg(const char *) name;
740 } */
741 char *name, *oname;
742 lwpid_t target;
743 proc_t *p;
744 lwp_t *t;
745 int error;
746
747 if ((target = SCARG(uap, target)) == 0)
748 target = l->l_lid;
749
750 name = kmem_alloc(MAXCOMLEN, KM_SLEEP);
751 if (name == NULL)
752 return ENOMEM;
753 error = copyinstr(SCARG(uap, name), name, MAXCOMLEN, NULL);
754 switch (error) {
755 case ENAMETOOLONG:
756 case 0:
757 name[MAXCOMLEN - 1] = '\0';
758 break;
759 default:
760 kmem_free(name, MAXCOMLEN);
761 return error;
762 }
763
764 p = curproc;
765 mutex_enter(p->p_lock);
766 if ((t = lwp_find(p, target)) == NULL) {
767 mutex_exit(p->p_lock);
768 kmem_free(name, MAXCOMLEN);
769 return ESRCH;
770 }
771 lwp_lock(t);
772 oname = t->l_name;
773 t->l_name = name;
774 lwp_unlock(t);
775 mutex_exit(p->p_lock);
776
777 if (oname != NULL)
778 kmem_free(oname, MAXCOMLEN);
779
780 return 0;
781 }
782
783 int
784 sys__lwp_getname(struct lwp *l, const struct sys__lwp_getname_args *uap,
785 register_t *retval)
786 {
787 /* {
788 syscallarg(lwpid_t) target;
789 syscallarg(char *) name;
790 syscallarg(size_t) len;
791 } */
792 char name[MAXCOMLEN];
793 lwpid_t target;
794 proc_t *p;
795 lwp_t *t;
796
797 if ((target = SCARG(uap, target)) == 0)
798 target = l->l_lid;
799
800 p = curproc;
801 mutex_enter(p->p_lock);
802 if ((t = lwp_find(p, target)) == NULL) {
803 mutex_exit(p->p_lock);
804 return ESRCH;
805 }
806 lwp_lock(t);
807 if (t->l_name == NULL)
808 name[0] = '\0';
809 else
810 strcpy(name, t->l_name);
811 lwp_unlock(t);
812 mutex_exit(p->p_lock);
813
814 return copyoutstr(name, SCARG(uap, name), SCARG(uap, len), NULL);
815 }
816
817 int
818 sys__lwp_ctl(struct lwp *l, const struct sys__lwp_ctl_args *uap,
819 register_t *retval)
820 {
821 /* {
822 syscallarg(int) features;
823 syscallarg(struct lwpctl **) address;
824 } */
825 int error, features;
826 vaddr_t vaddr;
827
828 features = SCARG(uap, features);
829 features &= ~(LWPCTL_FEATURE_CURCPU | LWPCTL_FEATURE_PCTR);
830 if (features != 0)
831 return ENODEV;
832 if ((error = lwp_ctl_alloc(&vaddr)) != 0)
833 return error;
834 return copyout(&vaddr, SCARG(uap, address), sizeof(void *));
835 }
836